See WARNINGS and PRECAUTIONS for additional important adverse events.

In clinical trials including 942 subjects, bleeding irregularities were the most common adverse event causing discontinuation of IMPLANON™ (etonogestrel implant) (see following Table).

Adverse Events Leading to Discontinuation of Treatment in 1% or More of Subjects in Clinical Trials

Adverse events that were reported by more than 5% of subjects in clinical trials appear in the following Table.

Adverse Events Reported in More than 5% of Subjects in Clinical Trials*

Other “Less Common Adverse Events” Reported in Less Than 5% of Subjects in Clinical Trials Include: Allergic Reaction, Alopecia, Anorexia, Anxiety, Appetite Increased, Arthralgia, Asthenia, Asthma, Breast Discharge, Breast Enlargement, Breast Fibroadenosis, Cervical Smear Test Positive, Constipation, Coughing, Crying Abnormal, Diarrhea, Dyspepsia, Dysuria, Edema, Edema General- ized, Fatigue, Fever, Flatulence, Gastritis, Hot Flushes, Hypertension, Hypoesthesia, Injection Site Reaction, Insomnia, Lactation Nonpuerperal, Libido Decreased, Migraine, Myalgia, Otitis Media, Ovarian Cyst, Pelvic Cramping, Premenstrual Tension, Pruritus, Pruritus Genital, Rash, Rhinitis, Sexual Function Abnormal, Skeletal Pain, Somnolence, Vaginal Discomfort, Vein Varicose, Vision Abnormal, Vomiting, and Weight Decrease.

Hypertrichosis has also been reported with use of progestin-only contraceptives.

Implant site complications were reported by 3.6% of subjects during any of the assessments in clinical trials. Pain was the most frequent implant site complication, reported during and/or after insertion, occurring in 2.9% of subjects. Additionally, hematoma, redness, and swelling were reported by 0.1%, 0.3%, and 0.3% of patients, respectively. See also WARNINGS, COMPLICATIONS OF INSERTION AND REMOVAL.

Changes in Contraceptive Effectiveness Associated with Co-Administration of Other Drugs

Anti-Infective Agents and Anticonvulsants

IMPLANON™ is not recommended for women who require chronic use of drugs that are potent inducers of hepatic enzymes because IMPLANON™ is likely to be less effective for these women.

Contraceptive effectiveness may be reduced when hormonal contraceptives are co-administered with some antibiotics, antifungals, anticonvulsants, and other drugs that increase the metabolism of contraceptive steroids. This could result in an unintended pregnancy or breakthrough bleeding. Examples include: barbiturates, griseofulvin, rifampin, phenylbutazone, phenytoin, carbamazepine, felbamate, oxcarbazepine, topiramate, and modafinil. Patients should use an additional non-hormonal contraceptive method when taking medications that may decrease the efficacy of hormonal contraceptives.

Anti-HIV Protease Inhibitors

Several of the anti-HIV protease inhibitors have been studied with co-administration of combination oral contraceptives; significant changes (increase and decrease) in the mean area under the curve (AUC) of the estrogen and progestin have been noted in some cases. The efficacy and safety of combination oral contraceptive products may be affected with co- administration of anti-HIV protease inhibitors; it is unknown whether this applies to IMPLANON™. Healthcare providers should refer to the labeling of the individual anti-HIV protease inhibitors for further drug- drug interaction information.

Herbal Products

Herbal products containing St. John's Wort (Hypericum perforatum) may induce hepatic enzymes and p-glycoprotein transporter and may reduce the effectiveness of contraceptive steroids.

Increase in Plasma Hormone Levels Associated with Co- Administered Drugs

Inhibitors of hepatic enzymes such as itraconazole or ketoconazole may increase plasma hormone levels.

Interactions with Laboratory Tests

Certain endocrine tests may be affected by IMPLANON™ use

a.Sex hormone-binding globulin concentrations may be decreased for the first six months after IMPLANON™ insertion followed by a gradual recovery.

b.Thyroxine concentrations may initially be slightly decreased followed by gradual recovery to baseline.

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